11/19/2011

Long time, no updates.
School and miscellaneous annoyances have done a great job of keeping me distracted. I'm currently working on a "analogue" harmonizer/octaver based on a phase locked loop. I'm aiming for a ridiculously high knob-count on this one. Maybe it's time to go modular..

The prototype circuit tracks the guitar surprisingly well and I'm sure tracking will be even better once I implement and test the complete circuit with more efficient signal conditioning.
Two parallel sections with independent controls will allow dual harmonies/octaves. E.g. a perfect 5th, two octaves up and a harmonic 7th, one octave down simultaneously. I currently get square wave outputs but the plan is to extend the available waveforms. Using example circuits from the CMOS cookbook, I've been able to generate a 'sine' wave. The scope picture shows the raw output from the first trials. After low pass filtering the signal, the blocky stair steps disappear. No scope photos of the current circuit, you'll have to take my word..